Xanthan gum has been found to be useful in an increasingly large number of applications in the food and industrial fields. This is true when the gum has been used primarily by itself but also when in combination with other active ingredients. In many such cases, synergistic effects have been observed which make certain unique gum blends particularly useful for certain operations. One limitation on further applications has been the presence of the enzyme cellulase in normally produced xanthan gum. This enzyme limits the practical use of xanthan gum in combination with cellulose or cellulosic compounds such as carboxymethyl cellulose and hydroxyethyl cellulose.
In the past, attempts to remove cellulase from xanthan gum have included (1) treating fermentation beer with mercurial compounds at high temperature, (2) treating xanthan gum presscakes with propylene oxide, and (3) heating high pH xanthan beer to about 93.degree. C. followed by cooling and neutralization. This last technique is not always reliable and also results in about a 10% loss of product.
U.S. Pat. No. 3,516,983 describes a process for removing proteinaceous impurities from xanthan beer by treating said beer with alkali metal hypochlorites at elevated pH followed by acidification and precipitation with a lower alcohol.